Two-motion switching system



June 2, 1953 J. KRUITHOF 2,640,882

TWO-MOTION SWITCHING SYSTEM Filed April 5, 1948 7 Sheets-Sheet 1 i Inventor L/flKOE KPH/7H0 Attorney June 2, 1953 J urr o 2,640,882

TWO-MOTION SWITCHING SYSTEM Filed April 5, 1948 7 Sheets-Shet 2 A Home y June 2, 1953 J. KRUITHOF TWO-MOTION SWITCHING SYSTEM Filed April 5, 1948 '7 Sheets-Sheet 4 A Home y J1me 1953 J. KRUITHOF TWO-MOTION swrrcumc SYSTEM 7 Sheets-Sheet 5 Filed April 5. 1948 M W.. U m m J Attorney June 2, 1953 J. KRUITHOF 2,640,382

' TWO-MOTION SWITCHING SYSTEM I Filed April 5, 1948 7 Sheets-Sheet e wpz P i D117] 7 omr DI' 1 Inventor -J4/ra5 K/PU/THOF A tlbrney June 2, 1953 J. KRUITHOF 2,640,382

TWO-MOTION SWITCHING SYSTEM Filed April 5, 1948 7 Sheets-Sheet 7 Inventor Attorney Patented June 2, 1953 UNITED STATES PATENT OFFICE TWO-MOTION SWITCHING SYSTEM Application April 5, 1948, Serial'No. 18,865 In the Netherlands September 13, 1947 Claims. 1

The present invention relates to a two-motion switching system in which with the aid of one or more multi-connecting switches a plurality of connections may be simultaneously built up and established via each switch.

The object is to provide a new and economical method for controlling these switches.

Such system may for example, be applied in an automatic telephone exchange or such like.

According to the main characteristic feature of the invention, a common mechanism, for instance a carriage, provided for all individual switches, of which a multi-switch is composed, may, by the energization of a power magnet, perform a selecting and/or hunting action namely for any number of these individual switches simultaneously under the control of a register controller for each of said individual switches.

In accordance with another feature of the invention, stationary contacts of a multi-switch cooperating with movable contact members on the common mechanism, are each electrically connected with the test conductor of a corresponding outlet common to all individual switches.

Characteristic potentials, present on the stationary contacts, each of which potentials characterizes a particular outlet or group of outlets, may be electrically extended to all those individual switch circuit and register controllers controlling same, for which the common mechanism performs a selecting and/or hunting action each time the corresponding movable contact members enter into contact with one of the stationary contacts.

In accordance with the invention for each common mechanism, there has been provided a single test relay, under control of which the selecting and/ or hunting movement can be ended by opening the circuit of the power magnet in which this relay is electrically connected with all individual switches and with the register controllers, controlling these switches.

As soon as one or more of the registers under control of which the mu1ti-.switch functions, is or are supplied with a characteristic potential via the stationary contacts and responds or respond to this potential, in accordance with a further feature of the invention, a circuit is closed from this register or these registers, in which this test relay is operated.

If more than one of these register controllers simultaneously responds to the afore-mentioned characteristic potential, in accordance with this invention, a double-test takes place, because means in the register controllers, via the individual switch circuits in question and one of the stationary contacts, cooperating with the common mechanism and electrically associated with the outlets seized thereby are connected to a direct current test potential associated therewith, this said potential being individually present for each outlet.

The register controller which successfully finished this direct current test, causes, according to another feature of this invention, that in the individual switch circuit in question an electromagnet is operated which prepares the switch for further extension.

The energization of this electro-magnet, in accordance with this invention, causes a second power magnet of the common mechanism to be operated, whereby dependent upon the operated position, taken by this mechanism and also dependent upon the meanwhile prepared individual switch one of the contact fingers in this last mentioned switch is brought into the operated position and is locked therein.

After locking the contact finger in question by the locking member, in accordance with this invention, contacts are opened and thus all electrical connections between the individual switch under consideration and the common mechanism and the circuit connected therewith, the test relay releases and the common mechanism is ready for starting or continuing the selecting and/or hunting movement for other individual switches.

As long as a connection remains established in accordance with this invention, the electro-magnet for the individual switch in question is maintained energized, which at the same time maintains locked the contact finger by means of the locking member.

When releasing the connection, the electromagnet is deenergized whilst the locking member and the contact finger are unlocked and the connection is released.

The invention will be described with reference to the accompanying drawings showing an embodiment of the invention in which:

Fig. 1 represents a plan view with some parts broken away to show an embodiment of a rotarytype switch in accordance with this invention.

Fig. 2 is a vertical sectional enlarged scale taken along line 2--2 of Fig. 1.

Fig. 3 is a partial plan view, taken over line 5--5 in Fig. 2;

Fig. 4 is a partial horizontal section similar to Fig. 3 showing one of the contact fingers in its operative position.

Fig. 5 symbolically, shows a multi-switch of the type to be described hereafter.

Fig. 6 represents a part of a register controller as well as a group selector in block schematic above same.

The group selector to be described below in the next switching stage, is shown in Fig. 7, whilst the subsequent selector is schematically shown in Fig. 8.

Multi-switches are known per-se for example as the so-called cross-bar switches; herein the control takes place in such a way that in each switch only one connection may be established at the time. The invention however, aims to provide the possibility of simultaneously establishing a large number of connections in each multiswitch.

A similar multi-switch which may be preferably applied has been described in applicants copending patent application Serial No. 14,215/ 48, filed March 11, 1948.

Since this switch is utilized in the present application, it seems desirable to first explain its operation.

This explanation will begiven for a single embodiment, asshown in Figs. 1, 2,3 and 4.

In the switch shown, the switch contacts are arranged circularly around a rotating carriage for making any group of these switch contacts. Referring specifically to the bank of contacts themselves there are shown'a plurality of groups or levels of arcuate contacting conductors l,

which are resilient or flexible andare shown to A comprise small finely wound wire springs. These contacting conductors are arranged (as shown in Fig. 4) so that they may be pressed against a plurality of yerticalcontacting bars, rods or conductors 2. (which may be flexible too) arranged in electrically parallel pairs and ingroups of five, corresponding to each one of the five flexible conductors l in any horizontal level. Thus, the conductors I of one group can be said to be arranged in parallel planes spaced at a given minimum distance from the conductors 2 of another group arranged in interleaved parallelplanes, and each conductor of one group is at :an angle to or crosses each conductor of the other. At each spaced crossing of a pair of conductors of each K kind there is provided a mechanically slidable finger 3, preferably made of an insulating material and provided with apertures 4 (Figs. 3 and 4) for receiving and holding the flexible conductors I. These slidable fingers 3 arearranged at right angles to and preferably between the two vertical conductors 2 of each pair, so that when they are pressed outwardly from the centre of the assembly herein shown they'will press the group of fiexible conductors l against the corresponding group of pairs of vertical conductors 2, to make contact therewith as shown in Figs. 2=and 4.

The number of conductors in each group, the number of horizontal levels of conductors, the number of radial vertical columns of conductors, and the number of independent contacting fingers 3 may be increased or multiplied from one up to any practical limit. For example, there are shown five electrical connections closed by the operation of each finger 3, each one of each of the connecticnsclosing electrically two parallel contacts, that is one contacton each conductor of the pair of conductors 2; and around the arc of the switch, there may be .provided say about eighty or more different vertical radial columns of pairs of conductors 2 as shown in Fig. 1, and vertically there may be provided say forty or more levels of conductors I.

In the embodiment shown,'the parallel planes or surfaces of conductors l and 2 including the the fingers 3 fit and slide.

4 slidable fingers 3, are mounted in four arcuate sectors each comprising a plurality of intermediate shelves 1 between a top plate 8 and a bottom plate 9. These shelves and plates are preferably made of insulating material and spaced by sleeves l0 and H and radially extending edges 12 and I3 of the sectors. Mounted on the top and bottom of each shelf 1 are arcuate, vertical walls 14 provided with apertures through which The sleeves l0 and l I are held together by long bolts 15 and IS, the lower ends of which are bolted to the lower frame or base H of the whole switch assembly, and the upper ends of the bolts I 6 are connected to a spider member 18 spaced above the top plate 8 by additional sleeves [9, to provide room for the ring 20 which carries the pairs of contacts or segments 2| and 22 of the carriage position indicating mechanism. Between the centre of the base frame I! and the spider I8 is mounted a fixed axle -24 about which a carriage assembly 25 rotates. Two gears 26 and 2Tare mounted on the carriage 25, the latter of which rotates the whole carriage assembly. The other gear 16 freely rotates on the sleeve" of the carriage 25 and drives a finger operatingmechanism through spur gears 29, 30 and 3|. These gears 26 and 2'! may be independently and non-concurrently driven from the common driving shaft 32 on which are mounted two slidably engageable gears 33 one of which is shown in Fig. 1, while the other is immediately beneath it for cooperation with the gears 28 and 21, respectively. These gears 33 are normally bent out of engagement by suitable rollers 35 mounted respectively on armatures 31 of separate clutch magnets 35 and 49, one of each of these parts being shown in Fig. 1 while the corresponding part is beneath it. By operating these magnets the rollers are lifted and the gears 33 are brought into engagement under their own tension.

In the operation of the switch, first magnet (see Fig. 5) is energized and the brush carriage 25 is rotated until proper marked contacts 2| and 22 (Fig. 2) are engaged. At this time magnet 40 is de-energized and the mechanical centering mechanism (see Figs. 2 and 4) comes into operation. This mechanism comprises a clutch plate 4| held against a'clutch surface on the gear 21'by a spring 42. The clutch plate H is provided with a lever 43 having a bifurcated end which cooperates with 9. lug 44 anchored in the base frame IT. This lever is maintained in the position by means of a strong spring 45. When the clutch has rotated-in the direction of movement of the carriage, the spring is tensioned so that when the clutch is stopped, it will reverse the rotation of the clutch, causing the pawl mechanism 41 mounted on the base plate 48 of thecarriage 25 to engage positively one of the centering teeth 49 of the ring 50 stationarily mounted on the frame base H by bolt l5 and IS. The teeth of the ring 50 are so arranged with respect to the position of the operating mechanism on the carriage and the ends of the fingers 3, that they will be in exact alignment when the pawl mechanism 4'! is in engagement with a face 49 of one of the teeth of the ring 50.

The electrical contacts for indicating the radial position at which thecarriageis to stop may be controlled by wiper contacts or by a roller type contact assembly 5| (as shown) mounted on the top plate 52 of the carriage assembly 25. The roller type contactors 53 and 54 are mounted on spring tension levers 55 and each roller electrically bridges the pair of contacts 2| and 2 2, which pairs are mounted in the arcuate nonconducting member 28. Each of the pairs of contacts 2| and 22 are provided with separate terminals 56 mounted outside the switch assembly above the top plate 8 as shown in Fig. 2. Similar separate terminals 51 and 58 to which conductors or wires may be soldered are provided at each end of each of the conductors I and respectively.

After the carriage 25 has been centered, the clutch magnet 59 is energized for a sufiicient time to cause the shaft 59 of the finger operating and locking mechanism on the carriage 25 to make one complete revolution.

This shaft 59 is journalled between plates 48 and 52 of the carriage mechanism, which plates are spaced at their outer end by posts 69 and 6| and brackets 62 and 63. Mounted on shaft 59 are two pairs of cams 64 and 65 which cooperate with separate cam followers 6 and 61 (see Fig. 3) for operating feeler and pusher arms or fingers 68 and 69 respectively. These arms are connected with slidable members and H having extensions 12 and 13 (Fig. 1) which are guided in slots and 11 in the top and bottom plates 52 and 48 respectively of the carriage mechanism. The cam followers on these members are maintained against the surfaces of their respective cams by springs 18 and 19 anchored to the carriage assembly at pins 80 and 8| respectively. There are provided separate arms or fingers 68 and 69 for each horizontal level of fingers 3, while the slidable members 10 and H are common to all the levels and extend the full height of the carriage between the plates 48 and 52. Each of the feeler fingers 68 is slidably positioned relative to the common member 10 by a common bracket 82 provided with slots through which the fingers 68 may slide (see Fig. 3).

Between each one of the feeler fingers and the common bracket 82 there are mounted springs 83 only sufficiently strong enough to maintain the feeler fingers in their retracted positions so that their shoulders 84 abut against a portion of the bracket 82 attached to the slidable member 10. Each of the fingers 68 is provided with an offset extension 85 which is bifurcated to engage the shoulder 86 at the adjacent end of its corresponding pusher finger 69.

The finger 69 continually urges its shoulder 86 against extension 85 by means of spring 81 mounted on the finger 69. These springs 81 merely maintain the fingers 69 in their normal retracted position with respect to the fingers 68. Each of the fingers 69 are journalled to slide in fixed members 62 and between the column 6| and member 63 which space the top and bottom plates 48 and 52 of the carriage 25. One of the fingers 69 of the carriage 25 is only selected for operation when its corresponding feeler finger 68 is moved to such an extent that its extension 85 pushes this finger 69 radially outwardly so that the projection 88 on this finger will engage the common pawl 89 mounted on the slidable member 1|. Then the operation of the member H by the rotation of cam 65 pushes the finger 69 through pawl 89 and projection 88 further outwardly to push in one of the fingers 3 of the switch. On the outward end of each finger 69 there is pivoted a bell crank lever 90 maintained in its normal position by a spring 9|. When the finger 69 is projected to operate the finger 3, the bell crank lever 90, upon retraction of the 6 slidable member '19 under the action of the spring 18, is caused to move and to operate the toothed locking ring 92 slidably mounted on stationary shelf 1 through slots 93 (see Fig. 3) to lock all the fingers 3 on that level in their operated and unoperated position. These toothed rings 92 have L-shaped cross-sections and teeth 94 and 95 on each edge thereof. These sets of teeth correspond in number to each of the fingers 3 in that level and are staggered with respect to each other. Each ring 92 is under the control of a separate magnet 96, and to save vertical space the magnets for separate rings may be placed between the conductor frame sectors shown in Fig. 1 so that every fourth vertical ring will be provided with a magnet in the same space between two sectors. The

magnets 96 predetermine the proper horizontal" level in which the desired finger 3 is to be operated, as the contacts 2| and 22 select the proper vertical row in which that finger 3 is to be operated. I

When one of the magnets 96 is energized, it moves its armature 91 carrying spring applied pawl 98, which cooperates with a first notch 99 in the ring 92, to slide or rotate the ring 92 into the first operative position. This movement places the feeler fingers 68 in line with an aperture between two adjacent teeth 94 on ring 92 and not in abutment with one of the teeth 94 as shown in Fig. 3. In this position, the finger 68 is permitted to project by the rotation of cam 64 radially outwardly far enough to also move the pusher finger 69 through extension acting on shoulder 86.

Then the following operation of slidable member H will cause the pawl 89 to catch the projection 88 and push the finger 69 further outwardly to move one of the fingers 3 into operated position 5. The end of finger 69 is formed so that it will not engage the teeth 94 when it is projected to operate the finger 3, as shown by the out out portion I98 in Fig. 2. When one of the fingers 3 is in the operated position 5 shown in Fig. 4, flexible conductors I are pressed against the vertical pairs of conductors 2 to make good electrical contact between them.

When the finger 69 is projected to operate the finger 3, one end of the bell crank lever is projected between two of the teeth 94 so that upon release or retraction of the member 10 the other end of the bell crank lever 90 will engage the projection l8! on member 10 to rotate the bell crank lever, thereby moving the slidable ring 92 in a clockwise direction into the second operative or looking position. In this position one of the teeth slides in front of the projection I03 of the operated finger 3 to maintain it in operated position, and all the other teeth 95 slide behind each one of the projections I03 on all the other fingers 3 in that level to prevent them from being operated. The sliding or rotation of the ring 92 by the action of the bell-crank lever 90, will move the ring into the position in which the pawl 98 will fall ito a second notch 99, and as long as the magnet 96 remains energized the ring will maintain all the fingers 3 in that level in locked position.

Thus, when the connection is finished and the magnet 96 for that level is deenergized, the spring I05 connecting each ring to its stationary shelf 1, 'restracts the ring to disengage the teeth 95 from all the projections I03, so that the operated finger 3 in that row returns to its normal position under the action of its corresponding spring I96.

In this switch there are in principle two kinds 7' of mutually. crossing conductors, for instance vertical and horizontal conductors, in which the con-.- ductors of one kind; for instance thehorizontal conductors, maybe broughtinto contact with all corresponding conductors of the-other kind, for instance the vertical ones, and in which in the same plane a plurality of conductors-of one kind may be brought simultaneously into contact'withan equal number of conductors of: the other kind by'means of a common member such as a. contact finger.

In order, however, to keep the schematic drawings showing the principles of operation of the switch as simple as possible, a number of symbols have been adopted as: indicated in: Fig. Sin which one conductor of each kindihas been represented, with the understanding that so manyconductors of one kind have been. represented as may simultaneously contact with an. equal number of conductors of the other kind, under the control of a single contact finger. In this figure the reference numbers 1' indicate 5 horizontal flexible conductors which by'means of a contacting finger may be moved simultaneously to paired vertical conductors 2, the said conductor pairs being permanently interconnected electrically. In order to indicate-the flexibility of. the conductors l, these have. been shown with a small, semi-circle, whilst each of the conductor pairs, 2 has been indicated by a single, vertical line. During the movement of one contacting finger the contacts a up to (2 incl. are therefore closed simultaneously. All five conductors I shown are located in the same horizontal level of the multi switch.

The left-hand ends of the; horizontal: conductors l as shown, correspond with the inlets of separate selectors or switches, through each of, which a. connection may be established, so that the multi switch may-be considered to be ccmposed of so many individual, selectors. or other switches as there are horizontal levels. of conductors l. The vertical conductors 2 are provicled in. common for all individual switches and in. accordance with the conception set out above, correspond with the bank multiples which extend over all, individual switches. Accordingly, each set of five vertical wires 2. influenced by the same contact finger corresponds to an. outlet of the switch under consideration, and will provide access toe. g. an outlet. of, a. selector or switch in a, subsequent, switching. stage or to any other circuit which may be connected to: a selector outlet.

The selector inlets are indicated symbolically. by 11.1 to m, whereas the selector outlets are in.- dicated symbolically by at to 62. though in a multi switch there may therefore, be provided a large number of inlets and outlets one of each onl is shown in a symbolic representation of this switch. An electro-magnet 96 (see Fig. 1) is associated with each inlet and is indicated sym bolically here by H. This magnet acts on a.

plurality of contacts, for instance H1 to Hi and.

influences in the above-described manner a slidable ring-shaped member serving a double purpose, namely for pro-determining the horizontal level in which the switching operation will take place and also for locking that contacting finger which has performed its switching action and also all remaining contact fingers in the same level in their non-operative position. This ringshaped member cooperates with contacts indicated schematically hereby for instance R11, R12 and R13 which are made only operative in the locking position.

Common toall individual selectors or switches inthismulti-switch, there'is provided a rotat able carriage, which is represented in the bottom part of Fig. 5. This carriage comprises contacting members cooperating with stationary contacts of the multi-switch and which serve for determining the vertical row in which a contact finger belonging to one of the levels has to be pushed. For each operative position of the carriage, corresponding with each vertical row of contacting fingers, there are provided a set of contacts 21 and 22, one pair of which has only been shown. The movable contact members on the carriage are arranged as roller contacts, indicatcd by 53 and 54 in Fig. 2, which, together with the corresponding feeder sectors 58, are symbolically represented here by the wipers indicated by I and II.

The rotation of the carriage takes place by operating a power magnet P1 (39 in Fig. 5) whilst the cams 64 and 65 in 6, which respectively serve for moving the feeler members 58 and the contacting finger pushing members 59, are moved under. the control of a second power magnet P2 (40 in Fig. 5).

The'switching operation of this nulti-switch wi l be described with reference to the accompanying figures in which Fig. 5 its lower part shows the essential elements of a register controller required for controlling a group selector which is shown in Fig. 6, whilst similar selectors have been indicated in the upper part of Fig. 5 and in Fig. 7, to precede and follow respectively the selector of Figs. 2 and 3.

For the sake of simplicity it is considered sufficient to explain the operation of the group selector, represented in Fig. 6 under. the control of the aforesaid register controller;

Selection of the desired outlet It is assumed that the setting of the switchestakes place basing on the principle of multipotential comparison, in which a characteristic, potential, indicating aparticular outlet or group of outlets, is'present on each idle selector outlet andthis potential is compared in the register controller with one reference potential from a group of similar, mutually differing potentials. In this register controller a reference potential is connected in accordance with the outlet or group ofoutlets to be selected, whereby each of these potentialsis related to the value of the selected digit. In the embodimentshown, use made of characteristic A. C. potentials which may mutually be distinguished, for example, by their phase angle. It is clear, however, that other characteristic potentials may be equally applied, such as the D. C. potentials disclosed in the U. S. patent application Serial No. 485,827, filed May 6, l9i3.

It isassumed that the digit in accordance with which the selector setting has to take place, has beenreceived in the register controller and has thereby caused that the contacting member RF isconnected to one of a group of reference po-- tentials cl to |0 in accordance with the dialled digit.

As soon as the register controller is ready to start the selection under consideration, the start selection contact SS is closed in a manner not further described, whereupon the relay Hpr is energized in a circuit via break contacts Dpz, Dml and make contact SS to ground. By make contact Hpl an operating circuit is closed for relay Ar via the wire In and break contact H1, which relay, thereby operates. This relay closes the circuit ofthe power magnet P1 by make conisolating jack BJ, and break contact A3.

tact as and via break contacts H3 and T1, in consequence of which the carriage is started and the movable contact members I and II are moved along the stationary contacts E. and D. The

above-mentioned characteristic potentials are connected to the wires cm of the individual selectors in the following switching stage (Fig. 8). As these selectors are identical to that repre sented in Fig. '7, it may be seen in the latter figure, that these potentials are connected to wire e1 (corresponding to wire em in the next stage) via a resistance of 20 ohms, contact of These potentials are therefore present on the wire e2 of the free outlets of the switch under consider- 'tials therefore, present on the contacts E of the different outlets are connected to the primary winding of the transformer TRl of the comparator through the preceding switch via contact member 1, front contact A2, back contact H4, wire b1.

If the thus connected characteristic potential corresponds in every respect with the reference potential, connected by the contact member to transformer TRz, the rectifier tube SVJ. becomes 'tensionless. This tube, responding to a potential difference between the transformers TRl and 'IRz, became ionised and caused the charge of the condenser 01. When the matching potential is reached by the switch and there is an equality of potential of both transformers, tube SV1 shuts off, so that the condenser may discharge through resistance R3. This results in an increase of the potential in the control gap of the discharge tube SVz, so that this tube ionises and closes a circuit from -l5O v. terminal, via resistance R4, the discharge space of the tube, winding of relay Wpr, front contact Hpe, through the preceding selector to wire d1, front contact A4, back contact R11 and winding of relay Tr to ground, thereby operating this relay. Relay Tr is a test relay provided in common for all individual switches with the carriage, which relay, by opening its back contact T1 stops the carriage in a position corresponding with the outlet in which the desired characteristic potential was met. In this position the contact memhers I and II are in contact with the stationary contacts associated with the wires c2 and d2 of this outlet respectively, whilst the feelers and the pushers on the carriage are standing in front of the vertical row of contact fingers, corresponding with this outlet.

Direct current test Relay Wpr in the register controller operates in series with relay Tr and closes through front contact Wm a circuit for the test relays Dtr and Dpr via the preceding selector wire c1, back contact RIs, front contact A1, contact member II, stationary contact D of the selected outlet and via wire (is to the inlet wire din of the subsequent selector. It proves from Fig. '7 that in the normal position of this selector, this wire is connected with battery through back contact A4 and a resistance of 240 ohms. If this battery is present both test relays will operate provided that not more than one register would try to seize the outlet under consideration, in which case a douin one register the test relays may become operative.

Through connection Assuming that the direct current test is successful, the operation of Dpr causes the opening of the circuit for relay Hpr, so that this relay releases. Via a back contact of relay Dpr the front contact l-Ipz is bridged, so that the above traced circuit of Dp-r is not opened by the release of Hpr. Subsequently Dpr opens at its back contact D274 the circuit of the slow relay Dmr, preventing the possibility that this relay might be energized after the operation of Wpr via front contact Wpz. Finally Dpr causes the removal of the operating ground for relay Ar by opening back contact D101. As a result hereof, the electromagnet H, which up to now was short-circuited by this operating ground, is energized in series with the winding of Ar via the front contact A3 towards a ground, which in the preceding selector is connected to wire e1 via the contact 63;: and the outlet cap of this selector. Whilst the relay Ar remains operated in this circuit the energization of the magnet H causes that the various contacts H1, H3 and H4 are opened and H2 is closed, whilst at the same time the slidable ring-shaped member is brought into the first operative position, whereby the horizontal row is predetermined, in which a contact finger will have to be pushed. Back contact H1 opens the operating circuit for Ar, which however has no further influence. Back contact H3 again opens the circuit of the power magnet P1 in the individual switch, which already had been opened in the common part by the back contact T1. Back contact H4 opens in the individual switch the circuit, via which the characteristic potential of the selected outlet was connected to the register controller, which however, has no further eifect, since the tube SVz remains ionised, independent of this potential. Finally the closure of front contact H2 causes the energization of the power magnet P2 in the circuit from ground via back contact R12. The operation of this power magnet causes the cams 64 and 65 of Fig. 3 to rotate, and the advance of all feelers on their carriage in order to scan, in which level the slidable ring member is brought in the first operative position. Only in this layer the pusher may become operative, causing the corresponding contact finger tobe pushed. At the end of this movement member of Fig. 3 caused the slidable ring member under consideration to slide into the second operative position so that the pushed contact finger in the corresponding level is locked in the operative position, whilst all remaining contact fingers of this level are locked in their nonoperative position. By pushing the contact finger, the contacts a to e were closed whereby the wires (11 to 21 of the individual switch in question are brought into contact with the wires ac to (12 of the selected outlet. Furthermore, ground is connected to wire c2 of the selected outlet.

Release of common part When sliding the ring-shaped member into the second operative position the contacts Rh to R13 were opened.

R12 opens thereby the circuit of the power magnet P2, so that it terminates its operation after a complete revolution of the cams 64 and 65 of Fig. 3. R13 opens the circuit via which the direct current test takes place, whilst R11 opens ble-test takes place in known manner and only 5 the circuit through which the relays Tr and Wpr are energized in series with the discharge, tube SVz. This tube extinguishes whilst Tr and Wpr are releasing. The closure of the back contact T1 produces the possibility that the power magnet Pl can again be operated under the control of one or the other individual selectors in this multi-switch. If this happens, both contact members I and II of the individual selectors under consideration are insulated by the opening of the back contacts H4 and RI3 respectively, whilst the test relay Tr is insulated herefrom by the fact that back contact R11 is open. The release of Wm as well as the opening of R11 causes the release of the double-test relays Dtr and Dpr in the register controller, so that this circuit is restored to the initial position.

Nonsuccessful direct current test If the direct current test is not successful e. g. by the simultaneous seizure of the selected outlet by a different connection, the relays Dtr and Dpr will not operate after the operation of Dtr so that a circuit is closed in which the slow relay Dmr may operate via front contact Wpz, and back contact Dpl. for relay Hpr at its back contact Dm-i so that in series with the discharge space of the tube SV2 the circuit for relays Wpr and Tr is opened and Wpr releases, which. in turn opens the direct current test circuit and the, circuit for relay Beer. The latter relay releases slowly and thus restores the register controller in the initial position, so the desired selector setting is again started.

Release of the connection The release of the connection is indicated by opening the ground. on wire 61 from the preceding selector. Relays Ar and the electromagnet H are de-energized whereby the ring-shaped member is pushed back towards the non-operative position in consequence of which the pushed contact finger may be restored to normal and the contacts a to e are opened and thereby the described connection is broken. Relay Ar again connects the test potentials to back contacts A3 and A4, so that from this moment. the selector is free to build up a new connection.

The present invention is in no way restricted to the special embodiment of the multi-switch,

in which the contacting conductors were provided in arcuate surfaces. Many modifications are possible within the scope of the invention, so that the described embodiment is not limitative in any way.

I claim:

1. In a switching system for establishing a plurality of connections, a multi-switch having a plurality of individual switches divided into sections, individual actuating means for operating said switch sections, a common mechanism mounted for movement into and out of co-operative relationshipwith said individual switch-section-actuating means, means for moving said mechanism into operatve relationship with a section of an individual switch, and means carried by said mechanism for operating said switch section actuating means after said mechanism has been moved into operative relationship with a switch section, the individual switches being mounted in stacked formation with the corresponding switch sections in aligned rows so that the common mechanism may be moved into operative relationship with all of the aligned switch sections in a. given row at This relay opens the circuit 12 the same time, the multi-switch being provided with a plurality of stationary contacts, one for each row of switch sections, and a contact mounted on said common mechanism, and cooperating with said stationary contacts when said common mechanism is moved, a test conductor for each row of switch sections, and means for connecting each of said stationary contacts with the corresponding test conductor.

2. In a switching system, the combination, as defined in claim 1, further comprising a circuit for each individual switch, register controllers for controlling the switches, sources of potential, means for connecting characteristic potentials from said sources to the test conductors, each of which potentials characterizes a particular outlet or group of outlets of said switches, means including the common mechanism for connecting said potentials to all those individual switch circuits and register controllers controlling said switches for which the common mechanism performs a switching action, said potentials being connected each time the corresponding movable contact members enter into contact with one of the stationary contacts.

3. In a switching system, the combination, as defined in claim 2, further comprising a test relay for the common mechanism, means for connecting said test relay to all individual switch section circuits, and means under control of a contact of said relay for energizing the mechanism moving means.

4. In a switching system, the combination, as defined in claim 3, further comprising means at each register controller for closing. the circuit through the test relay when the characteristic of a potential selected by said register controller bears a predetermined relation to that of the potential connected to said register controller via one of the stationary contacts and the common mechanism.

5. In a switching system, the combination, as defined in claim 4, further comprising means for performing a double test if more than one register controller tries to seize the same outlet, said means including means for connecting a direct current potential associated with the outlet to the test means in the register controller.

6. In a switching system, the combination, as defined in claim 5, further comprising an electromagnet in the individual switch circuit, and means to operate said magnet if the direct current test is successful, said magnet when operated acting to prepare said switch for completing the connection through said switch.

7. In a switching system, the combination, as defined in claim 6, in which the individual actuating means are a plurality of contact fingers in each individual switch and further comprising a power magnet associated with the common mechanism and under control of the electromagnet for moving one of said contact fingers and thereby operating one section of said switch, the finger moved depending on the position of said common mechanism and which individual switch has been prepared for operation, and means for locking said finger in moved position.

8. In a switching system, the combination, as defined in claim 7, in which the means for locking the contact finger comprises a locking member and contacts controlled by said member for disconnecting all electrical connections be-- tween the individual switch and the common 14 the electromagnet is de-energized and means to ole-energize said electromagnet when the connection is released.

JAKOB' KRUITHOF.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,097,307 Dyson May 19, 1914 10 1,812,617 Baker June 30, 1931 1,900,917 Deakin Mar. 14, 1933 1,925,264 Lomax Sept. 5, 1933 1,930,522 Keyser Oct. 17, 1933 

